The present disclosure relates generally to electronic faucets. Electronic faucets are often used to control fluid flow. Electronic faucets may include proximity sensors such as active infrared (“IR”) proximity detectors or capacitive proximity sensors. Such proximity sensors are used to detect a user's hands positioned near the faucet, and turn the water on and off in response to detection of the user's hands. Other electronic faucets may use touch sensors to control the faucet. Such touch sensors include capacitive touch sensors or other types of touch sensors located on a spout of the faucet or on a handle for controlling the faucet. Capacitive sensors on the faucet may also be used to detect both touching of faucet components and proximity of the user's hands adjacent the faucet
In capacitive sensing faucet applications, other components located near the electronic faucet may have unintended effects on the output signal from the capacitive sensors. For instance, a user touching a metal sink basin may induce a false capacitive signal at the capacitive sensors. Changes that occur below a sink deck may also cause false readings at the capacitive sensors.
In an illustrated embodiment of the present disclosure, a fluid delivery device includes an electronic faucet having a plurality of faucet components, and a primary capacitive sensor coupled to a component of the electronic faucet to sense a user touching or in proximity to the faucet component. The primary capacitive sensor provides an output signal. The fluid delivery device also includes at least one secondary capacitive sensor located on or near an item which causes unintended effects on the output signal from the primary capacitive sensor. Each secondary capacitive sensor also provides an output signal. The fluid delivery device further includes a controller coupled to the primary and secondary capacitive sensors. The controller determines a difference signal between the output signals of the primary and secondary capacitive sensors. The difference signal is used by the controller to detect when a user touches or is in proximity to the faucet component.
In illustrated embodiments, the at least one secondary sensor is at least one of a metal plate or electrode located near or coupled to the metal sink basin, a sensor coupled to a sense wire from the primary capacitive sensor, a sensor coupled to a drain to sense fluid going down the drain, a sensor coupled to a garbage disposal, and a sensor coupled to a fluid supply line. In other illustrated embodiments, the at least one secondary sensor is coupled to water-carrying equipment located below a sink deck, or to metal equipment or other equipment connected to water or located below the sink deck. In another illustrated embodiment, the at least one secondary sensor is used as an antenna to reduce electromagnetic interference (EMI) or electrostatic discharge (ESD) false activations.
In a further illustrative embodiment of the present disclosure, a fluid delivery device includes an electronic faucet having a spout, and an electrically operable valve to control water flow through the spout. A primary capacitive sensor is coupled to the spout, the primary capacitive sensor providing a primary output signal in response to a user input to the spout. A secondary capacitive sensor is coupled to a secondary component which causes unintended effects on the primary output signal from the primary capacitive sensor, the secondary capacitive sensor providing a secondary output signal in response to user input to the secondary component. A controller is coupled to the primary and secondary capacitive sensors, the controller determining a difference signal between the primary and secondary output signals of the primary and secondary capacitive sensors, the difference signal being used by the controller to control operation of the electrically operable valve.
A method of controlling an electronic faucet includes the steps of capacitively sensing a user touching or in proximity to a faucet component and providing a primary output signal in response thereto, and capacitively sensing input from an item which causes unintended effects on the primary output signal and providing a secondary output signal in response thereto. The method further includes determining a signal difference between the primary and secondary output signals to detect when a user touches or is proximity to the faucet component.
Additional features and advantages of the present invention will become apparent to those skilled in the art upon consideration of the following detailed description of the illustrative embodiment exemplifying the best mode of carrying out the invention as presently perceived.